The cutting of this path in itself was a tedious task, and gave some idea of the labour that would have been involved in tunnelling the rock. This narrow shelf, however, proved of inestimable value in handling the heavy overhead members of metal and setting them into position. The dimensions and weight of the latter had to be kept as low as possible to facilitate handling under the peculiarly cramped conditions. Actual erection was exciting and hazardous. The men had to be lowered by ropes and had to ply their tools while swinging in mid-air or when clinging to precarious footholds. However, the cumbrous overhead pieces were successfully set in position, the ends were bolted to brackets sunk deeply into the cliff faces, and from these girders the track floor was suspended, the ends resting on the solid edges of the rocky ledge, while one side was bedded against the wall.
Such is the story, as communicated to me by the engineers, of the origin and erection of what ranks as an unparalleled novelty in engineering. The “Hanging Bridge” was built in the Royal Gorge nearly 30 years ago, and although the first structure has been replaced by one of larger and heavier dimensions to accommodate weightier trains, the fundamental principle is precisely the same as conceived by Mr. Robinson.
Yet the “Hanging Bridge” is but one of many engineering wonders to be found on this railway. Go where one will over its 1,800 miles of track among the Rockies, and some striking and daring work confronts one at every turn. Here the railway threads its way through a winding abyss, there it passes over the crown of a towering peak, or toils laboriously up the side of a sheering cliff. No two miles are alike. In all it traverses five yawning canyons, each possessing a strange individuality, and crosses the mountain backbone by which the continent is split in twain by three different passes. Level sections are practically unknown. It is one continuous up-hill pull up the one, with a long coast down-hill with steam shut off, on the other, side—a switchback upon a stupendous scale.
Let us take the route over the Marshall Pass. At Poncha, on the Atlantic side, the line is at an altitude of 7,480 feet. The summit is six miles away by the iron road, but in that distance the train has to climb steadily at 211 feet to the mile over an extremely meandering route. The mountains become wilder and more broken as the summit is approached. The engineer took advantage of every natural facility that opened up to him. In turn the rail crawls along ledges cut in the mountain flanks, over lofty embankments, spidery trestles, doubling and redoubling upon itself in the most amazing manner. The occasional presence of snow-sheds draws attention to the fact that the metals are above the snow-line, and the many terrible dangers to which the track is exposed from avalanches and landslides.
Two huge engines are required to negotiate the heavy ascent, and at last, when the top is attained, the train is 276 feet in excess of two miles above the Atlantic on the eastern, and the Pacific on the western side, respectively. The tortuous path of the iron road is revealed below in a graphic manner. It may be seen in no less than four separate terraces, rising in steps one above the other, the lowest being almost invisible, connected by huge loops, until it finally winds away and is lost in the dim haze of the horizon. The descent is a replica of the ascent—the same gradient prevailing, viz. 211 feet to the mile. No steam power whatever is needed to drive the train. It is travel by mere gravitation alone, held in check by the powerful air-brakes.
Yet the railway is crossing the Divide at another point some miles to the north rises twice to an altitude exceeding 10,000 feet. This is on the extension of the original line from Pueblo to Leadville, where, after leaving the mining town, there is a tedious climb to Fremont Pass, where the track is laid 11,330 feet above the sea. A few miles to one side the line attains its maximum altitude, with 11,522 feet, at Ibex station, on a short branch road. After negotiating the Pass there is a sharp descent to Leadville junction, where another locomotive has to be hitched on to haul the train up a bank, rising 211 feet to the mile, to the summit of Tennessee Pass, lying at 10,240 feet, the highest point being gained in a tunnel, one mile in length, bored through the mountain peak.
On the southern section of the system the line passes through some of the wildest and most impressive country it is possible to conceive, and time after time the constructional engineer was puzzled sorely as to the best route for the road. It overcomes the Divide through the Cumbres Pass. On the up-hill pull the railway skirts a towering mountain spur, making a detour of four miles to circumvent the obstacle, and then bursts suddenly into a strange country. Strange monoliths rear up on all sides their fantastically wind- and weather-carved sides, glistening weirdly in the sunlight. The line swings round these grotesque evidences of Nature’s handiwork in a sharp bend known appropriately as “Phantom Curve,” and then disappears into the depths of the Toltec tunnel, which is carved through solid granitic rock for some 600 feet. The peculiarity of this work is that it is carried through the crest, and not the base of the peak, for the opposite portal of the tunnel stands on the brink of a precipice which drops plumb a quarter of a mile into the valley.
This gulf is spanned by a solid masonry bridge almost as wonderful as the Hanging Bridge. It recalls a swallow’s nest built under the eaves of a roof, for it is thrown across the gap to the opposite mountain ledge in the form of a balcony. Sudden emergence from the inky blackness of the mountain’s heart to this frail-looking link with the frowning wall opposite, and the depth of the fissure is decidedly startling. If the Eiffel Tower were planted in this gorge it would be dwarfed into insignificance, for its topmost platform would be over 500 feet below the railway track. To throw the bridge across this rift the men had to be slung out from derricks, manipulating their trowels from an unsteady platform—the snap of a rope, a missed footing, and certain death on the splintering crags below awaited the unlucky.
It is upon this same section that one traverses the wonderful Ophir Loop, by means of which the Divide at Dallas is negotiated. The towering Ophir mountain stands directly in the path of the line. A detour was impossible; the mountain had to be ascended, but in so doing the engineer imposed a fearful task upon the locomotives.
The rise is 4 per cent. In other words, for every 25 feet the train advances, it has to rise 12 inches. The line skirts the base of the mountain, describes a sharp semicircular curve, and then runs directly backwards, the track being parallel with that a few feet below. The Stelvio road over the Alps is a wonderful zigzag climb, but it does not double and re-double more than this ascent up Ophir mountain. Terrace after terrace of track is left below, extending through cutting, over embankment and high trestles, until the top is gained.